I wanted to post this in case someone else has the same problem I had with my Volvo Penta MS3C reverse gear.
My SB transmission was shifted at high RPM and glazed the clutch cone. How this happened is another story.
Anyway for some time now when shifted into forward my SB transmission would delay for about 10 seconds and then start turning the prop.
I read several online marine forum threads that seemed to indicate that the transmission could be taken apart and the clutch cone de-glazed with valve grinding compound.
I watched several You-tube videos for this problem with outdrives and my gear. Volvo outdrives are very similar to my gear.
Last Friday I removed the reverse gear, took it apart and lapped the sliding sleeve cones in the gear cones with valve grinding paste and put the transmission back together and it worked. The delay is gone and the transmission shifts instantly.
The job is formidable because the transmission is heavy. The good thing is most of the parts came apart as assemblies. There were shims everywhere to keep track of.
The takaway here is that if your old mecanical Volvo Penta reverse gear is delaying going ito gear the problem is most likely glazed clutch cones and the repair is not as difficult as most might think.